Design of multifunctional materials has triggered wide interest in a variety of fields like energy generation and storage, catalysis and sensing mainly as they can perform multiple functions simultaneously in time (C. Kim, B. T. N. Ngoc, K. S. Yang, M. Kojima, Y. A. Kim, Y. J. Kim, M. Endo, S. C. Yang, Adv. Mater., 2007, 19, 2341).
High aspect ratio one-dimensional structures of carbon such as nanotubes and nanofibers are considered to be most versatile for the fabrication of multifunctional materials considering their widespread applications, unique structure and fascinating mechanical, thermal and electrical properties. Imparting surface sensitive functions such as charge storage, ionic transport, reactivity, sensing ability etc. on these carbon morphologies can significantly broaden the techno-commercial importance of the materials by bringing radical changes in the design aspects of many systems.
Different techniques have been explored for implementing such nanomorphologies in practical devices.
Article titled “Metal-Polymer Nanocomposites for Functional Applications” by Prof. Dr. F. Faupel et al, DOI: 10.1002/adem describes the preparation of polymer-based nanocomposites by wet technique (2.2) consisting of metal nanoparticles in a polymer matrix and the resulting functional properties. The nanoparticles are produced by chemical methods to obtain exact particle size and shape. They are then dispersed in a polymer solution or in a monomer solution for subsequent polymerization.
Volume 50, Issues 2-3, 30 Nov. 2004, Pages 877-881 having doi:10.1016/j.electacta.2004.02.071, discloses polybenzimidazole (PBI) solutions of dimethyl acetamide (DMAc) which are electrospun to be webs consisting of 250-nm ultra-fine fibers. The webs are carbonized, activated by steam, to obtain activated carbon nanofibers (ACNFs).
Article titled “Synthesis of Poly[2,2′-(m-phenylene)-5,5′-bibenzimidazole] and Poly(2,5 polybenzimidazole) by Microwave Irradiation” by HE Rong-huan et al; in Chem. Res. Chinese Universities, 2009, volume 25(4), pgs 585-589 describes synthesis of PBI wherein 3,3′-diaminobenzidine tetrahydrochloride (DAB′4HCl′ 2H2O) is dissolved in polyphosphoric acid (PPA, 85% P2O5) under nitrogen inert atmosphere at about 140° C. followed by addition of isophthalic acid (IPA) at 170° C. and further heated at 200° C. to perform the polycondensation. The acid enwrapped was removed by soaking the solution in sodium bicarbonate, filtered, and washed with water till pH value of the washing water was about 7. The polymer was finally obtained by drying at 120° C. for at least 24 h.
Article titled “The effect of experimental parameters on the synthesis of carbon nanotube/nanofiber supported platinum by polyol processing techniques” by Seth L. Knupp et al, in Carbon, volume 4 6 (2008), pgs 1276-1284, describes preparation of carbon nanofiber supported catalyst wherein the carbon supports were exposed to a highly concentrated nitric and sulfuric acid mixture at 60° C., followed by drop wise addition of appropriate amount of precursor Potassium tetrachloroplatinate (K2PtCl4). The solution was heated at 125° C. for 2 h using an oil bath, under refluxing conditions and agitation. In the case of microwave irradiation method, the solution was heated in a domestic microwave oven. Platinized samples were dried at 100° C. in a nitrogen environment.
Article titled “Developments of Novel Functional Materials for Carbon Nanotube/Polymer Hybrid” by Tsuyohiko Fujigaya in Polymers—Vol. 58, No. 8 (August, 2009), discloses a polybenzimidazole (PBI)/CNT composite. Accordingly, PBI is wrapped around CNT followed by Pt loading on the CNT via a coordinative mechanism.
The literature reveals that the processes developed for the impartment of multifunctional characteristics include stringent experimental conditions like in-situ synthetic approaches, surfactant assisted methods or physical approaches, sophisticated instruments, series of different steps which may lead to hampering of certain desired and/or inherent properties.
Further, to date, most of the reports addresses the encapsulation of materials in the inner cavity of carbon nanotube that adopt complicated experimental conditions like gas-phase diffusion, filling from molten media or by using supercritial CO2 (P. M. Ajayan, S. Iijima, Nature, 1993, 361, 333; Skoulidas, D. S. Sholl, J. K. Johnson, J. Chem. Phys. 2006, 124, 1).
There is, therefore, a need to provide a multifunctional nanocomposite and a method for fabrication thereof which is simple and which does not destroy the inherent properties of the individual constituents of the nanocomposite.